<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    /* 68px * 29px */
    div {
      width: 1.813rem;
      height: 0.773rem;
      background-color: pink;
    }
  </style>
</head>

<body>
  <div></div>
  <script src="./js/flexible.js"></script>
</body>

</html>